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JoshWithrow
Contributor
Contributor

Upgraded Physical Memory, but VMWare Host Does Not Recognize It

We recently installed a 16GB upgrade into an ESXi 4.1 host.  The hardware recognizes the memory upgrade inthe post, BIOS, etc.  But VMWare doesn't notice.

Any ideas?

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Dave_Mishchenko
Immortal
Immortal

Welcome to the VMware Communities forums.  Generally memory is a plug and play operation for ESXi.  What sort of system are you using?

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JoshWithrow
Contributor
Contributor

I assumed it would be.  But I still can't get VMWare to recognize the new memory.

It's just an HP Proliant that's about 1 year old.  Dual quad core, 8 total cores.  RAID10.  750GB Disk Space.  It had 22GB RAM, we added another 16GB.  But in no way can I get VMWare to recognize the new hardware.

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Dave_Mishchenko
Immortal
Immortal

Do you know the specific model?  Does the server have any instructions for how the DIMM slots should be populated?  

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Josh26
Virtuoso
Virtuoso

Hi,

How did you add the 16 - what configuration? I'm curious how you got 22GB to start with too.

Most HP servers have a memory test available on bootup that will show you what is detected by the hardware.

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jdf28045
Contributor
Contributor

I work with poster.

The model is a Proliant DL360 it came with 22 gig.

Sold with 1 x 2gig dimm and was upgraded by them with 10 x 2gig dimms to make 22 gig.

The upgraded added was 1 x 16 gig dim to a existing un populated channel.

HP memory test shows all dimms working and accessable.  System shows 38 gig available.

VM still shows only the 22.

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farkasharry
Hot Shot
Hot Shot

Do you have the possibility to reinstall the ESX with an HP customized ESXi 4.1 installer CD?

We had similar issues on Dell Hardware and that helped.

*** If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful! *** vExpert 2019, VCAP-DCA,VCP,MCSE,MCITS and some more...
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JoshWithrow
Contributor
Contributor

We do.  Will re reinstall require us to wipe everything, or just the installation partition?  We are going to backup the guest OS's, but the shorter this "maintenance" will be, the better.  Looking for any insight you may have.  Thanks!

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DSTAVERT
Immortal
Immortal

The memory configuration you describe does not sound balanced and it will probably result in performance issues. Normal memory population guidelines would use equal numbers and sizes and speed of RAM modules in each memory bank. Each memory bank is assigned to a specific CPU.

-- David -- VMware Communities Moderator
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DSTAVERT
Immortal
Immortal

I would check the manual to make sure that the DL360 will actually support 38GB of RAM and or a 16GB module. I don't know what model but older versions only supported 32GB.

-- David -- VMware Communities Moderator
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COS
Expert
Expert

DSTAVERT is right. HP requires matching DIMM sizes in certain balanced configuration.

When you open the server and remove the top cover, there should be instructions on hoe each DIMM set is supposed to be populated. 

Your model if it is in fact just 1yr old should be able to take at least 64GB of RAM but it might not be able to take 16GB modules. You might need to count up how many DIMM slots you have and divide that into 64 and that should give the max size of a single RAM module you can insert.

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a_p_
Leadership
Leadership

If you have a HP partner who recommended this RAM population, you should consider to look for another one Smiley Wink

Assuming you are talking about the G6 model, have a look at http://h18000.www1.hp.com/products/quickspecs/13235_na/13235_na.html#Memory for DIMM population and important instructions. You may also go to http://h18004.www1.hp.com/products/servers/options/tool/hp_memtool.html to see what is possible. One issue could be the mix of dual-rank and quad-rank modules.

Depending on the current server firmware, you may also need to update this to the latest to support 16GB DIMMs.

André

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mike_laspina
Champion
Champion

Hi,

Since you are adding a 16GB kit there are only two 8GB DIMMS. You need a third 8GB for this to work optimally.

Regards,

Mike

http://blog.laspina.ca/

vExpert 2009

Message was edited by: mike.laspina Note: Make sure you VM does not have a memory resource limit set. Check VM Settings -> Resources -> Memory -> Limit

http://blog.laspina.ca/ vExpert 2009
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JoshWithrow
Contributor
Contributor

Mike, prior to the upgrade, 1 bank had 1 2GB DIMM, and the other banks all had 2 2GB DIMMs.  We transferred the 1 single DIMM in the bank to another bank, and put the 16GB DIMM in the newly created empty bank.

The server supports up to 192GB of ram, which means it does support 16GB per slot (they way I'm reading this).  There is serious penny pinching going on which is why we received a single DIMM.

Any further advice welcomed, and I'm grateful for the advice that we've received.  We're considering all options. Smiley Happy

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DSTAVERT
Immortal
Immortal

Penny pinching aside this should form a good stable foundation for your ESXi installation and as you have it configured it does not meet that goal. I would return the single module and get the appropriate number, size and speed to balance the RAM across both CPUs. Just because the BIOS reports the total amount of RAM and a simple memory check scan reports that all RAM is present and accounted for does not indicate that the RAM as installed will work or work well. If you end up with performance issues or functional problems, the cost of downtime or data loss will far outstrip any pennies pinched today.

-- David -- VMware Communities Moderator
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mike_laspina
Champion
Champion

Hi,

I recognise the cost issues, but consider this:

You have spent considerable time resolving the issue which costs money.

The DL360 G6 Must have 2 CPU's to go to 192GB of RAM or to use both 3 channel banks.

You have a three channel memory bus, but are forcing it to use only 1 at a time which makes your VM scheduled CPU threads wait 3 times longer for every single operation to or from RAM.

The vendor recommends populating it 3's for more that just performance reasons.

Regards,

Mike

http://blog.laspina.ca/ vExpert 2009
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